Rickettsia akari: Difference between revisions

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Rickettsia akari
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* Causes '''rickettsialpox'''
 
* Causes '''rickettsialpox'''
   
== Microbiology ==
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== Background ==
  +
=== Microbiology ===
 
 
* Disease caused by ''Rickettsia akari'', an intracellular Gram-negative bacterium
 
* Disease caused by ''Rickettsia akari'', an intracellular Gram-negative bacterium
 
* Unlike most rickettsiae, it has a plasmid
 
* Unlike most rickettsiae, it has a plasmid
   
== Epidemiology ==
+
=== Epidemiology ===
 
 
* Transmitted by the house mouse mite (''Liponyssoides sanguineus'')
 
* Transmitted by the house mouse mite (''Liponyssoides sanguineus'')
 
** Rodents are the reservoir
 
** Rodents are the reservoir
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== Clinical Presentation ==
 
== Clinical Presentation ==
 
 
* Incubation period of 7 to 14 days
 
* Incubation period of 7 to 14 days
 
* Present with fever, vesicular rash, and eschar
 
* Present with fever, vesicular rash, and eschar
 
** Headache also common
 
** Headache also common
* The eschar is painless, and appears as a papule about a week after innoculation, followed by vesicle that dries and leaves a brown or black eschar
+
* The [[Causes::eschar]] is painless, and appears as a papule about a week after innoculation, followed by vesicle that dries and leaves a brown or black eschar
 
* The rash is vesicular, but may be papulovesicular or any other type of rash
 
* The rash is vesicular, but may be papulovesicular or any other type of rash
 
** Lesions leaves black crust and heal without scarring
 
** Lesions leaves black crust and heal without scarring
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== Diagnosis ==
 
== Diagnosis ==
 
 
* Detection of a four-fold rise in convalescent titres by complement fixation or indirect fluorescent antibodies
 
* Detection of a four-fold rise in convalescent titres by complement fixation or indirect fluorescent antibodies
   
 
== Management ==
 
== Management ==
 
 
* Usually self-limited, resolving in 7 to 10 days, though antibiotics help
 
* Usually self-limited, resolving in 7 to 10 days, though antibiotics help
* Doxycycline 100 mg po bid for 2 to 5 days and 48 h after fever resolves
+
* [[Is treated by::Doxycycline]] 100 mg po bid for 2 to 5 days and 48 h after fever resolves
   
 
{{DISPLAYTITLE:''Rickettsia akari''}}
 
{{DISPLAYTITLE:''Rickettsia akari''}}

Revision as of 10:11, 12 December 2019

  • Causes rickettsialpox

Background

Microbiology

  • Disease caused by Rickettsia akari, an intracellular Gram-negative bacterium
  • Unlike most rickettsiae, it has a plasmid

Epidemiology

  • Transmitted by the house mouse mite (Liponyssoides sanguineus)
    • Rodents are the reservoir
  • Most cases are in New York, but it is found worldwide
  • Most likely rickettsiosis to be found in Ontario
  • Homelessness and IV drug use are risk factors

Clinical Presentation

  • Incubation period of 7 to 14 days
  • Present with fever, vesicular rash, and eschar
    • Headache also common
  • The eschar is painless, and appears as a papule about a week after innoculation, followed by vesicle that dries and leaves a brown or black eschar
  • The rash is vesicular, but may be papulovesicular or any other type of rash
    • Lesions leaves black crust and heal without scarring
    • Spares palms and soles
    • Resolves in two to three weeks
  • May find leukocytosis

Diagnosis

  • Detection of a four-fold rise in convalescent titres by complement fixation or indirect fluorescent antibodies

Management

  • Usually self-limited, resolving in 7 to 10 days, though antibiotics help
  • Doxycycline 100 mg po bid for 2 to 5 days and 48 h after fever resolves